Aural protective device



| T. REYNOLDS 42,619,960

AURAL PROTECTIVE DEVICE Dec. 2, 1952 Filed Dec. 4, 1950 JNVENTOR.

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Patented Dec. 2, 1952 UNITED STATES PATENT OFFICE AURAL PROTECTIVEDEVICE Lee T. Reynolds, Hollywood, Calif. Application December 4, 1950,Serial No. 199,365`

2 Claims.

This invention relates to an ear plug of the type designed for theprotection and prevention of injuries to the tympanic membrane or eardrum of the ear, and has for its principal object the provision of aplug of this character which will not interfere with the transmission ofsound vibrations to the ear drum at normal uniform levels, but whichwill act instantly to prevent sudden sounds of increased intensity frominstantly reaching the ear drum so as to relieve all sudden impacts onthe latter.

A further object of this invention is to provide what might be termed anear check valve which will act instantly and efficiently to preventsudden increases or decreases in air pressure from reaching the eardrum.

The invention is particularly useful for protecting the ear drum fromthe results of heavy gun nre, and is so designed that when thecompression Waves from the discharge of a large gun reach the ear, thesound passage to the ear drum will be instantly closed, and when thevacuum or 10W pressure wave which follows a compression wave reaches theear, the passage will be again closed to prevent sudden diiferentials inair pressure from occurring on the opposite faces of the ear drum whichmight result in injury or damage thereto.

The improved ear plug will also be found useful in shops, manufacturingplants, mining operations, etc., for protecting the ears from suddenextreme and unexpected sounds and noises. and yet allowing conversationand all other sounds of a uniform, continuous character to reach the eardrum without interference.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efficiency.These will become more apparent from the following description.

In the following detailed description of the invention, reference is hadto the accompanying drawing which forms a part hereof. Like numeralsrefer to like parts in all views of the drawing and throughout thedescription.

In the drawing:

Fig. 1 is a side view of the improved ear plug;

Fig. 2 is a longitudinal section therethrough, taken on the line 2-2 ofFig. 3;

Fig. 3 is an inner end view ear plug;

Fig. 4 is an outer end view thereof; and

Fig. 5 is a cross-section, taken on the line 5-5, Fig. 2.

In Fig. 1 the improved plug is illustrated subof the improved mediatethe extremities of,

(Cl. 12S-152) stantially full-size, and in the remaining figures thescale has been increased to substantially four times the natural size. i

The improved ear plug employs a cylindrical housing or barrel l0 closedat its outer extremity by means of an outer cap member Il and at itsinner extremity by means of an inner cap member l2. The cap members Iland l2 are shouldered to receive the extremities of the cylindricalbarrel l0, and the shouldered portion of the outer cap H is forced intothe outer extremity of the barrel with suilicient pressure tofrlctlonally retain itself in place therein. The edge: of the innerextremity of the barrel l0 is rolled inwardly into a dovetailed groovel5 in the shoulder of the inner cap member l2, after the internalmechanism is in place, to retain the three members'l, il, and l2permanently together.

The projecting portion of the inner cap member is conical and is axiallytapped to form threads I4 for receiving the threaded extremity of an eartube I3. The outer cap member Il is provided with a conical, axiallypositioned spring cavity It, the smaller diameter of which opens throughthe exterior of the cap member il. The inner cap member l2 is providedwith a similar conical spring cavity I'i, which opens to the interior ofthe ear tube I3. The larger diameters of the conical spring cavities arecut back to form spring clamping channels I 8.

The inner faces of the cap members Il and l2 are spaced apart within thehousing I0, and each of these faces carries an annular cup-shaped valveseat member i 9 having central sound ports 20. The seat members t overand are forced onto cir cular bosses formed on the inner faces of thecap members Il and l2 and have their flat faces facing each other inspaced-apart, parallel. relation within the housing I0.

A circular flutter between the flat faces of either seat member to closethe central sound passage or port 20 therein. The flutter valve disc 2|is formed or mounted on a valve shaft 22 interand at right angles to,the axis of the latter. The shaft 22 extends axially outward from bothfaces of the valve disc 2l through both the ports 20 and into theconical spring cavities IB and l'l. Each extremity of the shaft 22 isprovided with a spring-retaining ring or ange 23 set back from theadjacent extremity so that the extremities will project beyond theflanges 23 at each end of the shaft.

the smaller diameter of A watch-type hair spring 24 surrounds eachextremity of the shaft 2|. Hair springs of this type consist of a latsteel wire wound in a dat spiral so that normally the entire spring liesin a common plane. In this device, however, the circumferentialextremity of each spring 2A is clamped in one of the spring channels lbetween the adjacent seat the cap members 2|). The axial extremity ofeach spring is then slipped over one Vof the extremities of the shaft 2|so that it will lie against the flange 22 thereon. This distorts the twosprings outwardly so that they form conical, spiral helixes, as shown inFig. 2, which support the entire weight of the iiutter disc 2| and theshaft 2.2.

This manner of mounting the utter disc totally eliminates all frictionand the disc hangs suspended in the opposing thrust of the two hairsprings 2li.

A tubular rubber sleeve 25 is slipped over the eartube I3. The sleeve isprovided with an inwardly extending annular ridge 25 which ts into acircumferential receiving groove formed in the ear tube i3. Two exibleannular, dished anges 2 and 28 are formed on, and project about, theinner extremity of the sleeve 25 in spaced relation and serve to engagethe walls of the oral cavity to retain the ear plug in place therein.

It will be noted that the ange 2i is of smaller diameter than the flange28 so as to conform to the decrease in size of the natural ear cavity.The outer extremity of the rubber sleeve '.25 is flared outwardly toform a flexible cup 2d about the inner cap I2 to protect the valvemechanism from ear discharges and the like, and to form an outer seal inthe ear canal about the ear tube I3.

It can be seen that normal air vibrations or waves caused from sounds orother means can pass through the cavity I6, the outer port 2G, past thedisc 2|, and through the inner port 2&3 and the cavity I1 to the eartube I3 to vibrate the ear drum.

During all normal vibrations or waves the valve disc will simply flutteror vibrate between the double seat members I8 without closing eitherport 2U. Should'a sudden, loud noise occur, or should there be a suddenincrease in atmospheric air pressure, the velocity of the air throughthe outer port 2|] will act to force the valve disc instantly againstthe inner seat member I to seal the port 2li therein and so as toprevent a sudden or abrupt rise in air pressure on the ear drum.

Should a sudden or abrupt decrease in atmospheric pressure occur for anyreason, such as in the wake of a pressure wave, the pressure on theinside of the flutter valve 2| will force it outwardly against the outerseat member |9 to close the port 20 therein to prevent a suddenevacuation on the outer face of the ear drum, which might result indamage thereto.

member I9 and one or" It can be seen from the above that the passage tothe ear drum is normally open so that vibrations of all normal soundscan pass freely to the ear drum. The valve only functions on sudden andabrupt changes in sound volume or air pressure which act to create apressure differential on opposite faces of the flutter valve disc 2|.

It is preferred to form the barrel It and the caps and I2 fromnon-magnetic material, such as aluminum, and to form ythe shaft y22 andthe disc 2| from a resin plastic so as to avoid any interference due toadjacent magnetic fields.

While a specific form of the improvement has been described andillustrated herein, it is to be understood that the same may be varied,within the scope of the appended claims, without departing from thespirit of the invention.

Having thus described the invention, what is claimed and desired securedby Letters Patent is:

l. An aural protective device comprising a cylindrical barrel, inner andouter caps closing the opposite ends of said barrel and havingportionsextending into the barrel, said caps being each formed with a ,centralorice taperedtowards its outer end, a valve disc disposed loosely in thebarrel between the inner ends of` said caps having a centrally locatedshaft projecting from the opposite sides of the disc and into theorifices through the inner ends thereof, spiral springs disposed vaboutsaid shaft and located at opposite sides of said disc within the taperedorices, said springs being initially at and distorted longitudinally ofthe shaft to a conical formation and having their inner convolutionsconnected with the ends ofthe shaft and their outer convolutionsengaging the inner faces of the caps about the inner ends .of saidorifices, contraction of the springs being towards the disc inopposition to each other whereby the springs yieldably support the discbetween and in spaced relation to the inner ends of the caps and permitmovement of the disc towards either cap for closing the oriice thereof.

22 The structure of claim l, wherein an. annular valve seat member ismounted upony the inner end of each cap for `engagement by the disc whenthe latter is moved to a closed position, said seat members bearingagainst the outerfconvolutions of the springs andilrmly holding thesprings to the caps.

LEE T. REYNOLDS.

REFERENCES CITED The iollowing'references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,465,606 Reynolds Mar. 29, 19492,487,038 Baum Novr 8, 1949

